I have a question about grounding a 120/240 1ph 3w system. I am trying to determine if it is a violation of the 1999 NEC if their is a ground to neutral connection on the load and service side, and the two geound to neutral connections are connected. Thanks.
On the load and service side of WHAT?
The NEC allows one ground/neutral connection at the service location.
No connection to the grounded current carrying conductor is permitted on the line side of the service disconnecting means. That's all you need. It does not matter if the electrode you use is bonded to other electrodes or not.
No connection to the grounded current carrying conductor is permitted on < the [ line ]side of the service disconnecting means. That's all you
need. It does not matter if the electrode you use is bonded to other electrodes or not. > by Tom Horne
I am sure you meant the load side, correct?
I agree with most of you here that in general the grounded conductor shall not be connected to the grounding conductor on the load side of the service disconnect. However, for two or more buildings supplied from a single service a rule is given in 1999 NEC Section 250-32(b)(2) that requires that the grounded conductor be connected to the equipment grounding conductor at the second building or structure. Additionally, in the 1999 NEC Section 250-140 the grounded conductor was permitted to ground ranges, dryers, wall-mounted ovens, counter-mounted cooking units in existing dwellings other than mobile homes and recreational vehicles. This rule is no longer in the NEC and was, according to my research, placed in the NEC during WWII to reduce the use of copper during war time. It is my understanding that California is still using the 1999 NEC. Is this correct or did they update?
You're correct of course. I did mean the load side. You're also right about separate buildings being an exception under the US NEC in the absence of any other metallic pathway between the two buildings but best practice is still to wire the second building with a separate Equipment Grounding Conductor (EGC).
-- Tom Horne
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